Subject: Clear coating over decals

I've got a bike with a decent paint job and decals put on by the
previous owner. I've heard that I can clear coat right over these and
it will look good. True? Can I clear coat from a spray can and get
acceptable results? Any prep work I should be aware of? I'd hate to do
this and then have it look worse than before.

Thanks to all who've been so helpful in the past.

-Rich